Just finished my first destashing project of this year! It's a bottle cozy knit from an oddball single skein of bulky single-ply wool. I found it in one of my drawers partially up as a legwarmer. Since I have already traded the rest of the yarn and this yarn is a pain to frog, I decided to make use of the half-knitted object and transform it into a cozy. It's useful because my stainless steel water bottle tends to sweat all over the place whenever I fill it with ice-cold water.
Edit: I added this project to Ravelry and my pattern "notes" ended up a fairly descriptive pattern. Here it is in case anyone who is not on Ravelry and wants to knit up some stashbuster cozies:
Water Bottle Cozy:
Cast on desired amount of stitches (needs to be a multiple of 4 for neater decreasing). Knit 2x2 ribbing in the round for desired length until the cozy reaches the curve of the bottom of the bottle. Starting on the next row:
Row 1: Decrease by p2g the first pair of purl stitches then every other group of purl stitches until the end of the row.
Row 2: Knit in pattern (should be *P1, K2, P2, K2, repeat from * to end.)
Row 3: Decrease by p2g the remaining pairs of purl stitches. Stitches should now be in a K2, P1 pattern.
Row 4: Knit all stitches.
Row 5: Divide stitches into 6 even groups. Place marker if desired. Knit until 2 stitches before marker, then K2tog. Repeat until end of the round.
Row 6 and on: Repeat decrease pattern dictated in row 5. Knit rows until 6 stitches remain on needles. Cut yarn and draw yarn tail through stitches. Draw the hole closed. Pull the tail through center of hole and weave in on wrong side of cozy. Weave in cast on tail. Finished!
Note: I cast on 26 stitches so for my decreases, I had to separate my stitches into alternating groups of 6 stitches and 7 stitches for the decreases. You would not run into this problem with a multiple of 4 stitches.
Also, my bottle is a 27oz Kleen Kanteen. I'm not sure how this would work out with other yarn weights or wider/narrower bottles. For flat-bottomed bottles, you could probably ignore the row 1-3 instructions, knit a purl ridge, then start on row 4.